Flexible gear.



K. ALQUIST.

FLEXIBLE GEAR.

APPLICATION FILED JULY25. 1912.

' Patented June 1, 19150 maul-pas I I KARL ALQUIST, or scHnnao'rAnY, newYORK.

' Specification of Letters Patent.

FLEXIBLE GEAR.

Patented Junejl, 1915.

Appfication filed July 25, 1912. serial-newness.

'- of New York, have invented certain new and useful Improvements inFlexible Gears, of-whieh; the following is a specification.

My invention relates to flexible gears and more especially togears builtup of a plurality'of elements or laminations and provided with helicalteeth whereby pressure exerted by =a cooperating gear upon the toothportions'o'f the elements will operate to deflect them axially andthereby effect a yielding action in the direction of rotation. I havealreadyshown and described in my co-pendingrapplicationSeri-al No.639,210, filed July 18,1911, a flexible gear of the character referredto. 1

The object of the present invention is to provide a construction whichshall be stronger and more durable than any of the flexible gearsheretofore produced.

In the flexible gears made up of elements or laminae of uniformthickness and each tooth carried upon an arm or extension, in creasedflexibility can be accomplished only by increased length of arm orextension, and

this increased length of arm or extension canonly be made at asacrificein the strength of the arm. In order to overcome this objection, Ipropose to form each element of my built up .gear with alternate teethleft out, so that in undercutting below the base of the tooth to formthe arms or extensions sufficient metal will remain at'the base of thearm or extension to'elfectually sustain the stresses imposed upon thetooth in operation.

My invention is illustrated in the accompanying drawing forming a partof this specification, in which-- I Figure 1 shows in side elevationsegments of two-elementswith their teeth in stepped relatiomFig. 2 isaside elevation of a segment of an element having its teeth of greaterthickness .thanthe-"arms or extensions thereof; Fig- 3 isa developedsection taken upon the pitch-circleof agear built up of elements shownin Fig. 2; Fig. t is -a view-similar to Fig. 2 showing mod fication;Fig. 5 is a section of the form of element. shown in Fig. t; and Fig. isa side elevation of an element with the teeth in 'groups withcorresponding spaces between.

As shown in Fig. 1.-the individual ele ments '1 are'of uniform thicknessas when made preferably of sheet steel. The teeth 2 are formed on'theperiphery thereof and between the teeth deep notches 3 are outwhereby'relatively long arms or extensions 4: between the-base of thetooth and the uncut portion of the element are formed. Any two adjacentelements will be mounted upon a suitable hub/so that the teeth of oneelement are-in stepped'relation to the teeth of the next element. Thisarrangement enables me to make-an assembled gear with the required vnumber of teeth and with the individual teeth of any element supportedon arms of sufiicient length to afford the necessary flexibility and atthe same time. on account of the increasing width'of the arm orextension as it approaches its base, the necessary-strength is provided.A gear built up of elements of uniform thickness, as shown in Fig. 1,would, of course, have spaces on opposite sides of each individualtooth.

In order-to make use of the waste room, incident to the elements ofuniform thickness, I make'the thickness of the toothed portions doublethat of the main or central portions of the elements. This may be doneby cutting the teeth in thick disks and machining off oneor both sidesof the central portions to just over one-half of the thickness of theteeth so as 'to practically close the gaps. while still leavingindividual freedom to-the teeth after assembling. I have shown part'ofsuch a ring element in Fig. 2. As indicated, I may let the outer partsof the extensions have the same thickness as the teeth, so as tostrengthen the support, and

suitably machine down the inner parts to somewhat less than thethickness'of the central portion, so as to give-freedom of movement.

In Fig. 31 have further shown a developed view of a section through thepitch circle of part of a built up wheel, which plainly indioatesthismethod of closing up the gaps between the tooth elements,'so that theteeth of the built up wheel will become practically continuous. Thisfigure also "showjsthe several plates and their teeth uniformly advanced'one with respect to the other on their common axis with theresult that the faces of the teeth instead of extending parallel to saidaxis form helices. \Vhcn the teeth in the driving and driven gears areproperly formed the action of one tooth on another will be rolling; incharacter as distinguished from sliding as is the case with ordinaryspur gearing. other way, there is practically a point of contact betweenengaging teeth which progressively moves from one side of the completegears to the other.

Theteeth of each element may be finished separately, and then accuratelyassembled, or they may be roughly finished, and finally out, after beingassembled. and suitable provisions may be made for preventing the teethfrom moving axially during the final cutting operation.-

In the form of my invention described with reference to Fig. 2, theflexibility is mainl provided by the extensions 4, and the centralportion 5 yields very little or not at all, and is firmly clampedbetween the corresponding: portions of the adjacent eleto increase thismass it is necessary to increase the radial dimension of the extension.The individual freedom reqmred between two adjacent teeth on the samering element,

is. however. not very large, as the error in the cutting in such a casewould be small, and the more considerable errors, which theflexibilityhas to correct, depend on the width of the wheel and thealinement of the shafts. Thus it will not be a disadvantage it therelative flexibility between two such tooth elements is loss thanthedotal flexibility. and I may make the extensions comparatively shortandinstead have a wider ring portion, the outer part of which isflexible, as indicated in Fig. 4. I may further make this centralportion so as to form three concentric parts, 5, 6, 7. of which theouter one 5 will be. partly subjected totorsional stresses and willtransmitthe spring action over a large portion. of the middle part (3.where the thickness is reduced as shown in Fig. 5, and the inner part 7is firmly clamped in the ordinary way. By extending the spring actionover a. large surface in this way 1 obtam a large flexibility with aradially comparatively narrow central element, and thisconstruction ison. that account more specially suitable for pinions, where the diameterhas to he kept down, while the .type indicated in Fig. 2 is moresuitable for larger Wheels, and also for cases where the elements arebuilt up in sections.

, In the examples il ustrated the elements have been provided withone-half of the To state the matter in an- -number of teeth of thecompleted wheel. It

. third of the teethof the complete wheel. It

ing from the spirit of the invention,'and I may adopt any methods forefliciently producing the individual toothed ring elements, and foraccurately assembling them to form a complete wheel or pinion.

\Vhat I claim as new and desire to secure by Letters Patent of theUnited States, is,-

1. A gear comprising a central or body portion provided with a pluralityof radial arms yieldable axially of the gear with their outer endsthickened and shaped into tooth sections which collectively form helicalteeth.

2. A helical gear built up of a. plurality of elements. each elementhaving a plurality of tooth sections constructed to yield axially uponthe application of a tangential force and the number of tooth sectionson each element being less than the number of tr th of the completegear.

3. A helical Q'ear built up of a plurality of transverse elements, eachelement havine a plurality of radial arms yieldablc perpendicularlyto'thc plane of the element and provided at their outer ends with toothsections.

4-. A helical gear built up of a plurality of transverse elements. eachelement having a plurality of radial arms vieldable perpendicularly tothe plane of the element and provided at thoi r outer ends with toothsections oi a thickness ereater than said element.

A helical gear built up of a plurality of transverse elements. eachelement having tooth portions extending outwardly therefrom, the numberof said tooth portions on each element being one-half the whole numberof teeth of the complete gear and the thickness of said tooth portionsbeing substantially double the thickness of the body or central portionof an element.

6. A helical gear built upof a plurality of ring elements, each elementhaving a plurality of arms or extensions carrying tooth sections attheir ends and said ring elements being reduced in thickness at a pointinside the tooth portions to render said arms In Witness whereof, I havehereunto set I or extensions flexible perpendicular to the my hand this24th day of July, 1912. plane of the element.

7. A helical gear having a plurality of Witnesses KARLIALQUIST' toothsections yieldable axially under the f wedging action of a companiongear and. ar-' BENJAMIN B. HULL,

ranged in staggered or stepped relation. HELEN Onronn.

Copies of this patent may be obtained for five cents'eaehg by addressingthe Commissioner of Patents,

' Washington, D. G.

